IIRC some inverters are able to sync up with alternative power sources, but the documentation is extremely limited and seems to be reserved mostly for large-scale systems. I know my Solaredge system has slowly been implementing using both at the same time, but the documentation is pretty unclear as to how this works. I know at the very least it'll allow you to use a 2-wire start to kick a standalone generator on when the batteries are low, but don't know much else about how it's currently set up